People have known for thousands of years that raw honey has many medicinal properties such as wound healing and antibacterial activity. Honey was widely used for medicinal purposes in the ancient world and is still common in Africa, India and the Middle East. However, despite extensive research, the healing properties of honey have not yet been fully elucidated.
Most honeys are in some way antibacterial, some more than others. Honey with high antibacterial activity, typically has high levels of hydrogen peroxide (H2O2) which is referred to as “peroxide activity” (PA). Other properties of honey commonly known to underpin its antibacterial activity are low pH and high sugar content (high osmotic effect). It is likely that the historical use of honey as a wound healing agent stems from its antibacterial activity.
The PA activity of honey is derived from an enzyme called glucose oxidase. Like many enzymes, glucose oxidase is inactivated by light and heat. The stronger the light and/or heat, the faster it is inactivated. Room temperature and low light, given enough time, will also reduce the glucose oxidase activity. Glucose oxidase only becomes active when honey is diluted. The precise reasons for the activation of the enzyme upon dilution are still not clearly known.
Two honeys, known as jelly bush and manuka honey, are interesting because they can have anti-microbial activity due to some property other than the production of hydrogen peroxide, low pH or high sugar content. Both jelly bush and manuka are plants that are Leptospermum species. The antibacterial activity of these honeys is referred to as the non-peroxide activity (NPA). Unlike PA, NPA is stable to moderate heat, light and even gamma radiation.
Honey is a complex, naturally occurring, mixture of components. After processing of the collected nectar by bees (including addition of various components one of the most important of which is diastase), the water content of the modified nectar evaporates slowly from about 70 to 80% by weight, to about 17 to 18% by weight, eventually providing ripe honey. Ripe honey, therefore, has a low water activity, which contributes to its high osmotic effect and therefore its antibacterial activity. However upon dilution, honey is susceptible to fermentation, typically because of the presence of the ubiquitous yeasts such as zygosaccharomyces rouxii. 
Honey has previously been used to treat a wide range of indications. For example, Al-Waili (Al-Waili N. S., J Medicinal Food, 2004, 7(2), 210-222) reported on the effect of unadulterated honey on bacterial conjunctivitis, induced in mice, compared to appropriate antibiotics, oflaxocin and chloramphenicol. Better outcomes on bacterial conjunctivitis, such as reduced redness, swelling and eradication of bacterial infection, using honey compared to oflaxocin or chloramphenicol eye drops or control (no intervention) were observed.
The use of unadulterated honey in treating other ocular disorders has also been reported. Mansour (Mansour A. M., Clinical and Experimental Ophthalmology, 2002; 30: 149-150) reported the use of topical honey on 16 consecutive patients with corneal oedema. Epithelial oedema was immediately cleared in all corneas, improving visual acuity, and decreasing pain associated with bullous keratopathy. Initial application of honey caused a stinging sensation but its effect was short lasting. In addition, Emarah (Emarah M. H., Bulletin of Islamic Medicine, 1982, 2(5), 422-425) treated 102 patients, with various ocular diseases not responding to conventional treatment, with unadulterated honey by application to the conjunctival sac. Greater than 80% of patients improved with the honey treatment and no patient got worse with this treatment. A transient stinging sensation and redness of the eye was reported but was not severe.
Direct application of unadulterated honey to, for example, a site of injury, can be difficult because of honey's inherent properties such as varying viscosity and natural “stickiness”. Use of unadulterated honey can also be time consuming, messy and impractical. The problems associated with the application of honey may result, for example, in low patient compliance.
The present invention arises from the unexpected discovery that honey having non-peroxide antibacterial activity, for example honey derived from Leptospermum species, may be diluted to have a water content at which honey would be normally expected to undergo bacterial spoilage. Further, the dilute honey may be filtered in a more facile manner and has a reduced stinging sensation when applied to the eyes over undiluted honey. The diluted honey retains significant antibacterial properties and in addition to its other beneficial properties has a shelf life.